Apparatus for correlating different portions of a projected image and method of assembly therefor

ABSTRACT

This disclosure relates to apparatus for correlating different portions of an image displayed upon a screen and to a method of assembling the apparatus. Illustratively, the apparatus includes a correlating or indexing member which is suspended upon a flexible strand to allow the correlating member to be moved across the screen, and a plurality of guide points about which the strand is disposed. The guide points are located with respect to the display screen to permit the indexing member to be moved across a substantial portion of the display screen. The indexing member has an opening therethrough in which there is disposed spring means to interconnect a first portion of the flexible strand to a second portion of the flexible strand and also to place a predetermined tension upon the flexible strand.

limited States Patent inventor Bruce E. Crayton 400 Plymouth Ave.,Rochester, N.Y.

Appl. No. 782,961 Filed Dec. 11, 1968 Patented Aug. 17, 1971 AssigneeEastman Kodak Company 7 Rochester, N.Y.

APPARATUS FOR CORRELATING DIFFERENT PORTIONS OF A PROJECTED IMAGE ANDMETHOD OF ASSEMBLY THEREFOR 2,943,141 6/1960 Knight 3,374,546 3/1968.lustis ABSTRACT: This disclosure relates to apparatus for correlatingdifferent portions of an image displayed upon a screen and to a methodof assembling the apparatus. lllustratively, the apparatus includes acorrelating or indexing member which is suspended upon a flexible strandto allow the correlating member to be moved across the screen, and aplurality of guide points about which the strand is disposed. The guidepoints are located with respect to the display screen to permit theindexing member to he moved across a substantial portion of the displayscreen. The indexing member has an opening therethrough in which thereis disposed spring means to interconnect a first portion of the flexiblestrand to a second portion of the flexible strand and also to place apredetermined tension upon the flexible strand.

15 Claims, 7 Drawing Figs.

[52] U.S. Cl. 178/735, 3 3/80, 178/783 [51 Int. Cl A43] 13/02, H0 lj29/89 {501 Field 0! Search 178/785, 7.83, 33/80, 86, I03; 346/139 B,I40; 353/40 [56] References Cited UNITED STATES PATENTS 2,244,549 6/194]Blakeslee 33/80 PATENIED m1 1 um SHEET 1 [If 2 WM 4) M ATTORNEYSPATENTED AUG] 7:971

SHEET 2 OF 2 BRUCE E. CRAYTON INVENTOR.

{MU M AT TORNE Y5 APPARATUS FOR CORRELATING DIFFERENT PORTIONS OF APROJECTED IMAGE AND METHOD OF ASSEMBLY THEREFOR BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates to devicesfor displaying images and more particularly to apparatus for use inconjunction with such display devices for correlating or comparingdifferent portions of the displayed image.

2. Description of the Prior Art There are many types of devices whichare capable of displaying images such as a television monitorincorporating a cathoderay tube or a microfiche reader including adisplay screen. Often it is desired to display a single image upon thescreen to allow an observer to analyze the displayed information.Depending upon the desired use of the information, it would be helpfulto provide means for underscoring or readily identifying particularportions of the displayed image. For example, if the operator desires torecord particular information from the displayed image, it would behelpful to underline those portions which are to be recorded so as tofocus the attention of the operator upon this portion of the image.

Further, it may be desirable to present an image containing a pluralityof columns of information and to correlate data in one column with datain another column of the image.

Straight edges or crosshairs have been mounted upon projection displaydevices so as to be movable across the display screen. The mechanism formoving the straight edges or crosshairs have been designed for aparticular display device and can not readily be adapted to other typeof devices or to screens of varying size and format. These mechanismshave tended to be complex and expensive without the desired adaptabilityto other formats. Further, these mechanisms have not had the capabilityof easilyadjusting the angular position of the straight edge to allowthe operator to compare bits of information that are not disposed uponthe same line or are disposed upon a line that is skewed with regard tothe format of the displayed image.

Therefore, it is an object of this invention to provide a new andimproved assembly for movably mounting an indexing or correlating memberwhich may be adapted to many, different sizes and formats of displaydevices.

It is a further object of this invention to provide a new and improvedassembly for mounting and indexing member which may be readily adjustedto correlate portions of the projected image which are skewed withrespect to the format of the projected image.

SUMMARY OF THE INVENTION In order to accomplish these and other objectsof this invention, apparatus is provided for movably mounting anindexing or correlating member with regard to the display screen of adisplay device. More particularly, there are provided a plurality ofguide points which are mounted with regard to the display device inorder that the indexing member may be suspended for movement across thedisplay screen upon a flexible strand disposed about the guide points.The indexing member may take the form of a tubular member having anopening therethrough with first and second supporting members suspendingboth ends thereof from the flexible strand. Means for interconnecting afirst portion of this strand through the opening of the indexing memberto a second portion of the strand includes a spring means for placing atension upon the strand.

In an illustrative embodiment of this invention, there are provided fourguide points taking the form of pulley assemblies about which the strandis suspended. The pulley assemblies may be located to define aquadrilateral figure. More specifically, a fist loop of the flexiblestrand is disposed about the first and second pulleys and a second loopof the strand is disposed about all four of the pulleys. The firstsupport member is connected to the first loop and the second supportmember is suspended from a portion of a second loop, Illustratively, thesupport members may include handle portions to be manually grasped tomove the indexing member across the display screen, and projecting feetto space the indexing member from the display screen thereby reducingthe possibility of scratching the display screen.

An illustrative method of mounting the indexing member includes thesteps of inserting a first loop of the flexible strand through theopening of the indexing member, attaching the spring to the first loop,and connecting a J-shaped member to the spring. The guide points orpulley assemblies are affixed with respect to the display screen to forma quadrilateral figure, and the flexible strand is disposed about thepulley assemblies. The ends of the flexible strand are tied together andthe J-shaped member is withdrawn from the opening thereby stretching thespring. Finally, the spring is connected to a portion of the flexiblestrand to place a tension upon the strand determined by the length ofthe J-shaped member.

The invention, and its objects and advantages, will become more apparentin the detailed description of the preferred embodiments presentedbelow.

BRIEF DESCRIPTION OF THE DRAWINGS In the detailed description of thepreferred embodiments of the invention presentedbelow, reference is madeto the accompanying drawings, in which:

FIG. ll shows a perspective view of a display device on which theapparatus for mounting an indexing member in accordance with theteachings of this invention may be disposed;

FIG. 2 is a plan view of the assembly for mounting an indexing member inaccordance with teachings of this invention;

FIG. 3 is a detailed, perspective view of a support member forsuspending an indexing member from a flexible strand;

FIG. 4 shows an exploded view of a. pulley which may be incorporated inthe assembly of FIG. 2;

FIGS. 5A and 5B show how the support members may be adjusted withrespect to the strand in either direction; and

FIG. 6 shows how the support members may be manually manipulated to movethe indexing member across the display screen.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Because certain parts ofdisplay devices and related apparatus are well known, the followingdescription is directed in particular to those elements forming, orcooperating directly with the present invention; elements that are notspecifically shown or described herein are understood to be selectablefrom those known in the art.

With regard to the drawings and in particular to FIG. 1, there is shownan image display device 26 including a display screen or surface 28 uponwhich is disposed a guide assembly 10 in accordance with the teachingsof this invention. With regard to FIGS. 1 and 2, the guide assembly 10includes an indexing or correlating member 12 which is suspended from aflexible strand or cord 18 to be movably mounted across the surface ofthe display screen 28. More particularly, the indexing member 12includes first and second ends which are at tached, respectively, tosupport members 14 and 16. The strand 18 is disposed about a pluralityof guide points formed by pulley assemblies 20, 21, 22 and 23. Theindexing member 12 as shown in FIG. 2, takes the form of a tubularmember having an opening or passageway 13 therethrough. A first portionidentified by the numeral 18a may be inserted within the opening 13 andconnected to a spring 58. More particularly, the spring has a pair ofhooks 60 and 62 which are respectively connected to the portion 18a andalso, as will be explained later, to a second portion of the strand 18by a .l-shaped member 64. The J-shaped member 64 includes a hook 65which engages the hook 62 of the spring 58. The J-shaped member 64further includes a folded, enlarged portion 66 which is disposedsubstantially perpendicular to the member 64 and is to prevent theinsertion thereof into the opening 13.

7 With regard to FIG. 3, there is shown a detailed view of the supportmember 14 including a tubular portion 36 for receiving as shown in FIG.2 the indexing member 12. Further, the support member 14 includes anupright portion 32 from which extend a pair of feet 34 and 35 to raisethe support member 14 and the indexing member from the surface of thedisplay screen 28 to thereby minimize the scratching of the surface ofthe display screen 28. A handle 30 extends upwardly from the tubularportion 36 to be manually grasped as shown in FIG. 6 for moving theindexing member 12 with respect to the display screen 28. The supportmembers 14 and 16 serve to suspend the indexing member 12 from thestrand 18. As shown in FIG. 3, the upright portion 32 includes a guidegroove 38 which is aligned with the direction in which the handle 14 ismoved along the strand 18. As shown in FIGS. 2 and 3, the first portion18a of the strand 18 is inserted within the opening 13 through anopening 40 within the handle 14. Further, the

guide groove 38 serves to stabilize the handle 14 upon the .dis-

play screen 28. 7

With regard to FIG. 4, there is shown an exploded view of the typicalassembly 20 including pulley 48 which is rotatably mounted upon a post52, which in turn is secured to a base 50. The pulley 48 is held uponthe post 52 by a screw 42 which is inserted through a washer 44 to bethreadably received within the post 52. As can be seen in FIGS. 2 and 4,the strand 18 is received within a recess of the pulley assemblies 20,21, 22

, and 23, and in particular, within a recess 49 of the pulley 48. A

significant aspect of this invention is the adaptability of the 7 guideassembly 10 to many different sizes and formats of display screens. Inorder to accomplish this object, each of the pulley assemblies and, asshown in FIG. 4, pulley assembly is provided with a layer 54 of asuitable adhesive which serves to attach the pulley assemblies 20, 21,22, and 23 to the image display device 26 or as shown in FIG. 1,directly to the display screen 28. In order to protect the layer 54adhesive before its placement, a protective layer 56 is applied to thelayer 54 of adhesive.

As shown in FIG. 2, the flexible strand 18-is disposed about the pulleyassemblies 20, 21, 22 and 23 and the indexing member 12 is suspendedfrom first and second portions of the strand 18. More particularly, aU-shaped or first portion 18a is disposed with the opening 13 and is thebight of portion 18a is connected to the hook 60 of the spring 58.Further, a first loop of the flexible strand 18 is formed by portions18f, 18c and 18b about the pulley assemblies 20 and 21. A second loop ofthe strand 18 is formed about the pulley assemblies 20, 21, 22 and 23and includes those portions identified by the numerals 18g, 18d, 18s,18i, and 18h. The second loop is completed when portions 18c and l8i aretied together in a knot 68.

One of the significant aspects of this invention is the adaptability ofthe guide assembly 10 to a many different formats and sizes of displayscreens. The guide assembly 10 is sent to the user in the form of a kit,which is assembled by the user upon a cathode-ray tube or upon thedisplay screen of a microform reader; the kit includes an extendedlength of the strand 18, a pair of support members 14 and 16, fourpulley assemblies 20, 21, 22, and 23, a J-shaped member 64, a spring 58,and an extended length of the indexing e member 12. The first step inmounting the guide assembly 10 is the placement of the pulley assemblies20, 21, 22, and 23 either upon the display device 26 itself or upon thedisplay screen 28 to thereby define the operative area over which theindexing member 12 may be moved. The layer 56 is removedto therebyexpose the layer 54 of adhesive material; as shown in FIG. 1, thepulleys 20, 21 22, and 23 are inserted within the comers of the displayscreen 28 and are fixedly held thereto by the layer 54 of adhesive tothereby define a quadrilateral figure. Next, the indexing member 12 iscut to the desired length approximately equal to the distance betweenthe opposite sides of the quadrilateral figure. Then, the first andsecond ends of the indexing member 12 are inserted within the tubularportions 36 of the support memberszl4. and 16. The U-shaped, firstportion 180 is inserted through the openingl3 of the indexing member 12and the bight of portion 18a is connected to the hook 60 of the spring58. In turn, the hook 62 of the spring 58 is connected with the hook 65of the .I-shaped member and the free ends of the strand 18 are pulleduntil the enlarged end 66 engages the support member 16 and prevents thefurther insertion of the J- shaped member '64. The ends of the strand 18extending from the opening 40 of the support member 14 are disposedabout the pulley assemblies 20 and 21 to form the first loop and thendisposed about the pulley assemblies 20, 21, 22, and 23 to form thesecond loop. The ends of the strand formed by portions 18i and 18e aretied to form the knot 68. Next, the J- shaped member 64 is withdrawnthereby expanding the spring 58 and placing the strand 18 undertension.i When the J- shaped member 64 has beenwithdrawn, the' hook 62of the spring 58 is inserted within the knot 68 a to thereby completethe assembling process of the guide assembly 10. It is particularlynoted that the length ofthe J-shap'ed member 64 is particularly'chosento stretch the spring 58 a desired amount thereby placing the desiredtension upon the strand 18.

' With regard to FIGS. 5A and 513, there is shown how the angularorientation of the indexing member 12 may be adjusted with regard to theformat of the displayed image. More particularly, as shown in FIG. 5A, aportion 18f may be grasped securely between the fingers while the handle30 of the support member 14 is pushed upward. It is noted that the othersupport member 16 is fixedly secured with respect to the knot 68 so athat the end of indexing member .12 supported by member 14 will beraised with respect to the end of the indexing member 12 supported bythe member 16. Conversely, as shownin FIG. 5B, the portion 18b may begrasped and the handle 30 may be moved downward to thereby readjust theposition of the end of the indexing member 12 supported by the member 14to a lower position. As the support member 14 is pushed upward ordownward, a corresponding length of the portion of the strand 18 slidesfreely over the hook 60 to thereby allow the desired adjustment. In thismanner, the angular position of the indexing member 12may be adjusted ina desired manner to thereby facilitate the correlation between differentportions of the image projected upon the display screen 28.

After the guide assembly 10 has been mounted upon the display screen 28and the angular position of the indexing member 12 has been adjustedwith respect to the strand 18, the indexing member 12 may be movedupwardly and downwardly by grasping either of the handles 30 of thesupport members 14 and 16 as shown in FIG. 6. With regard to FIGS. 2 and6, by manipulating support member 16 upwardly, portion 181' is movedupwardly, portion 18g is moved downward and portion 18f is movedupwardly so that both support members 16 and 14 are moved upwardly thesame distance thereby maintaining the relative angular position of theindexing member 12. In a similar manner, as support member 14 ismanipulated downward, portion 18f is likewise moved downward, portion180 is moved upwardly, and portion ,18i is moved downward to therebydisplace support member. 16 the same distance that support member 14 hasbeen displaced. Thus there has been shown a guide assembly for anindexing member. which is'readily adapted to be mounted on displayscreens of varying size and format. In addition, the indexing member maybe readilyv adjusted to form any desired angle with respect to theformat of the displayed image.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

lclaim: I

1. Apparatus for installation of a display surface, and for correlatingvarious portions of an image projected onto the display surface, saidapparatus including:

' 'a member for correlating the different portions of the displayedimage, said member for correlating having an opening between first andsecond ends,

aflexible strand including at least first and second portions,

means for suspending said strand with respect to the display surfaceincluding'a plurality of guide points disposed so that said member forcorrelating may be movably disposed over the display surface, 1

means disposed within said opening of said correlating member forinterconnecting said first portion to said 'second portion,

spring means for placing a predetermined tension upon said flexiblestrand and I a removable tension determining member for determining theamount of tension to be placed upon said flexible strand by said springmeans.

2. The invention as defined in claim 1, wherein said guide pointscomprise a rotatable pulley for e receiving said strand.

3. The invention as defined in claim 1, wherein said rotatable pulleysare rotatably mounted upon a base member, said base member having apressure sensitive adhesive material for afi'ixing said base member withrespect to the display surface.

4. The invention as defined in claim 1, wherein there is furtherincluded first and second support members for mount ing said correlatingmember from said flexible strand, said first and second support membersincluding handle portions for manipulating said member for correlatingacross the display surface.

5. The invention as defined in claim 4, wherein said first and secondsupport members each include foot portions for spacing said member forcorrelating from the display surface.

-, 6. Apparatus for installation on a display screen upon which an imageis displayed, comprising:

first, second, third, and fourth guide' points; v

an indexing member for correlating different portions of the displayedimage, said'me'mber for correlating including first and second ends anda passageway extending from said first end to said second end, saidfirst, second, third,

and fourth guide points being located with respect to the display screento facilitate the movement of said indexing member across the displayscreen;

a flexibie cord including a first loop disposed about said first andsecond guide points and a second ioop disposed about "said first,second, third and fourth guide points,

' said first loop having a first portion, said second loop hav- -ing asecond portion;

first and second members for supporting said first and second ends ofsaid indexing member from said first and second portions, respectively,of said first and second loops;

means disposed within said opening for interconnecting said firstportion to said second portion and including spring means for placing apredetermined tension upon said flexible cord; and

removable means for selectively determining the amount of tension to beplaced upon said flexible cord by said spring means.

7. Apparatus for correlating various portions of an image projected upona display surface, said apparatus including:

a member for correlating different portions of the displayed image, saidmember for correlating having first and second ends, and a passagewayextending from said first end to said second end, i

a flexible strand including at least first and second portions,

means for suspending said strand with respect to said dis play surfaceincluding a plurality of guide points disposed so that said member forcorrelating may be moved across the display surface, and

means disposed within said passageway for interconnecting said firstportion to said second portion including a spring connected to saidfirst portion and a tension determining member having a first end to bereleasably connected to a said spring and a second end having means forpreventing ,,the insertion thereof into said passageway, said tensiondetermining member being withdrawn from said passageway to enable saidspring to be attached to said second portion and to place apredetermined tension upon said flexible strand. a

8. A method of mounting and assembling. an indexing member having firstIand second ends and a passageway between the first andsecond ends ofsaid indexing member, said indexing member supported respectively byfirst and second support rn'e mbers from a flexible strandhaving'firstand second ends said flexible strand .being disposed about a pluralityof guide points, said method including the stepso'fz locating saidplurality of guide points to define the a ra-over which said indexingmember is to be moved, forming a first loop of said'strand with a bightand inserting said first loop through said'passageway;

connecting a spring member to said bight of said first loop;

attaching a tension determining member of predetermined length to saidspring member, said tension determining member including means forengaging said second end of said indexing member; disposing said strandabout said guide points;

securing said first and second ends of said strand together;

and

I withdrawing said tension determining member from said second end ofsaid passageway and securing said spring member to said strand, saidpredetermined length being chosen to place the correct degree of tensionupon-said strand.

9. A method as claimed in claim 8, wherein said plurality of guidepoints includes first, second, third, and fourth guide points, and saidstep of disposing further including forming a second loop of said strandabout said first and second guide points, and forming a third loop ofsaid strand about said first,

' second, third and fourth guide points.

10. A method as claimed in claim 9, wherein said first and second endsof said strand are tied'together in a knot between said third and fourthguide points and said spring member is secured to said knot.

11. Apparatus for installation of a display surface, and for correlatingvarious portions of an image disposed upon the display surface, saidapparatus being adjustable and including:

a member for correlating the different portions of the displayed image,said rnember for correlating including firstand second ends, and apassageway extending from said first end to said second end, I

a flexible strand having at least first and second portions,

means for suspending said flexible strand with respect to the displaysurface including at least first, second, third, and fourth guide pointsdisposable to define a quadrilateral figure having at least first andsecond opposite sides and to facilitate the movement of said member forcorrelating across the display surface, and

means for adjustably interconnecting through said passageway said firstand second strand portions,

spring means for placing a tension upon said flexible strand,

and

means for selectively determining the amount'of tension to be placedupon said flexible strand by said spring means.

12. Apparatus as claimed in claim 11, wherein said member forcorrelating is disposable between said first and second opposite sides.

13. Apparatus as claimed in claim 12, wherein said spring meansis'disposable within said passageway and is interconnectable betweensaid first and second strand portions; and said flexible strandincludesa first loop disposable about said first and second guide points, and asecond loop disposable about said first, second, third and fourth guidepoints.

14. A method of installing on a display surface an adjustable apparatusfor correlating various portions of an image projected onto the displaysurface, said apparatus including an angularly adjustable indexingmember having a passageway between first and second ends thereof, aflexible strand, first .and. second support members for supporting saidindexing member, a plurality of guide'points for receiving said flexiblestrand, and means for placing a predetermined tension on said flexiblestrand when received by said guide points and when supporting saidindexing member, said method including the s I disposing said strandabout said guide points in second and third lobps; 1 tying the ends ofsaid strand together in a knot; and withdrawing said tension determiningmember from the second end of said indexing member and securing a saidspring member to the strand knot, the predetermined length of saidtension determining member being chosen to placethe desired degree oftension upon said strand. 15. The method defined in claim 14 whereinsaid plurality of guide points includes first, second, third and fourthguide points, and said step of disposing said strand about said guidepoints further including forming said second loop of said strand aboutsaid first and second guide points, and forming said third loop of saidstrand about said first, second, third and fourth guide points. v

1. Apparatus for installation of a display surface, and for correlatingvarious portions of an image projected onto the display surface, saidapparatus including: a member for correlating the different portions ofthe displayed image, said member for correlating having an openingbetween first and second ends, a flexible strand including at leastfirst and second portions, means for suspending said strand with respectto the display surface including a plurality of guide points disposed sothat said member for correlating may be movably disposed over thedisplay surface, means disposed within said opening of said correlatingmember for interconnecting said first portion to said second portion,spring means for placing a predetermined tension upon said flexiblestrand and a removable tension determining member for determining theamount of tension to be placed upon said flexible strand by said springmeans.
 2. The invention as defined in claim 1, wherein said guide pointscomprise a rotatable pulley for e receiving said strand.
 3. Theinvention as defined in claim 1, wherein said rotatable pulleys arerotatably mounted upon a base member, said base member having a pressuresensitive adhesive material for affixing said base member with respectto the display surface.
 4. The invention as defined in claim 1, whereinthere is further included first and second support members for mountingsaid correlating member from said flexible strand, said first and secondsupport members including handle portions for manipulating said memberfor correlating across the display surface.
 5. The invention as definedin claim 4, wherein said first and second support members each includefoot portions for spacing said member for correlating from the displaysurface.
 6. Apparatus for installation on a display screen upon which animage is displayed, comprising: first, second, third, and fourth guidepoints; an indexing member for correlating different portions of thedisplayed image, said member for correlating including first and secondends and a passageway extending from said first end to said second end,said first, second, third, and fourth guide points being located withrespect to the display screen to facilitate the movement of saidindexing Member across the display screen; a flexible cord including afirst loop disposed about said first and second guide points and asecond loop disposed about said first, second, third and fourth guidepoints, said first loop having a first portion, said second loop havinga second portion; first and second members for supporting said first andsecond ends of said indexing member from said first and second portions,respectively, of said first and second loops; means disposed within saidopening for interconnecting said first portion to said second portionand including spring means for placing a predetermined tension upon saidflexible cord; and removable means for selectively determining theamount of tension to be placed upon said flexible cord by said springmeans.
 7. Apparatus for correlating various portions of an imageprojected upon a display surface, said apparatus including: a member forcorrelating different portions of the displayed image, said member forcorrelating having first and second ends, and a passageway extendingfrom said first end to said second end, a flexible strand including atleast first and second portions, means for suspending said strand withrespect to said display surface including a plurality of guide pointsdisposed so that said member for correlating may be moved across thedisplay surface, and means disposed within said passageway forinterconnecting said first portion to said second portion including aspring connected to said first portion and a tension determining memberhaving a first end to be releasably connected to a said spring and asecond end having means for preventing the insertion thereof into saidpassageway, said tension determining member being withdrawn from saidpassageway to enable said spring to be attached to said second portionand to place a predetermined tension upon said flexible strand.
 8. Amethod of mounting and assembling an indexing member having first andsecond ends and a passageway between the first and second ends of saidindexing member, said indexing member supported respectively by firstand second support members from a flexible strand having first andsecond ends, said flexible strand being disposed about a plurality ofguide points, said method including the steps of: locating saidplurality of guide points to define the area over which said indexingmember is to be moved, forming a first loop of said strand with a bightand inserting said first loop through said passageway; connecting aspring member to said bight of said first loop; attaching a tensiondetermining member of predetermined length to said spring member, saidtension determining member including means for engaging said second endof said indexing member; disposing said strand about said guide points;securing said first and second ends of said strand together; andwithdrawing said tension determining member from said second end of saidpassageway and securing said spring member to said strand, saidpredetermined length being chosen to place the correct degree of tensionupon said strand.
 9. A method as claimed in claim 8, wherein saidplurality of guide points includes first, second, third, and fourthguide points, and said step of disposing further including forming asecond loop of said strand about said first and second guide points, andforming a third loop of said strand about said first, second, third andfourth guide points.
 10. A method as claimed in claim 9, wherein saidfirst and second ends of said strand are tied together in a knot betweensaid third and fourth guide points and said spring member is secured tosaid knot.
 11. Apparatus for installation of a display surface, and forcorrelating various portions of an image disposed upon the displaysurface, said apparatus being adjustable and including: a member forcorrelating the different portions of the displayed image, said memberfor correlating including first and second ends, and a passagewayextending from said first end to said second end, a flexible strandhaving at least first and second portions, means for suspending saidflexible strand with respect to the display surface including at leastfirst, second, third, and fourth guide points disposable to define aquadrilateral figure having at least first and second opposite sides andto facilitate the movement of said member for correlating across thedisplay surface, and means for adjustably interconnecting through saidpassageway said first and second strand portions, spring means forplacing a tension upon said flexible strand, and means for selectivelydetermining the amount of tension to be placed upon said flexible strandby said spring means.
 12. Apparatus as claimed in claim 11, wherein saidmember for correlating is disposable between said first and secondopposite sides.
 13. Apparatus as claimed in claim 12, wherein saidspring means is disposable within said passageway and isinterconnectable between said first and second strand portions; and saidflexible strand includes a first loop disposable about said first andsecond guide points, and a second loop disposable about said first,second, third and fourth guide points.
 14. A method of installing on adisplay surface an adjustable apparatus for correlating various portionsof an image projected onto the display surface, said apparatus includingan angularly adjustable indexing member having a passageway betweenfirst and second ends thereof, a flexible strand, first and secondsupport members for supporting said indexing member, a plurality ofguide points for receiving said flexible strand, and means for placing apredetermined tension on said flexible strand when received by saidguide points and when supporting said indexing member, said methodincluding the steps of: locating a said guide points on the displaysurface to define the area of the display surface over which saidindexing member is to be moved; forming a portion of said strand into afirst loop with a bight and inserting said first loop through the firstend of said indexing member and through the passageway therein;connecting a spring member to the bight of said first loop; attaching atension determining member of predetermined length to said springmember, said tension determining member including means for engaging thesecond end of said indexing member; disposing said strand about saidguide points in second and third loops; tying the ends of said strandtogether in a knot; and withdrawing said tension determining member fromthe second end of said indexing member and securing a said spring memberto the strand knot, the predetermined length of said tension determiningmember being chosen to place the desired degree of tension upon saidstrand.
 15. The method defined in claim 14 wherein said plurality ofguide points includes first, second, third and fourth guide points, andsaid step of disposing said strand about said guide points furtherincluding forming said second loop of said strand about said first andsecond guide points, and forming said third loop of said strand aboutsaid first, second, third and fourth guide points.